The statues in Bandos's throne room frequently drop cut gems from sapphire through diamond, making the room popular for some gem hunters who can kill the statues easily. Completion of The Chosen Commander is required for access to the throne room.

Some gems can be purchased, stolen or sold to a gem shop identified with a red gem icon on the world map.

Any standard rock (clay, copper, iron, coal, etc.) has a 1/282 chance to produce a gem (sapphire to diamond) when mining (without an amulet of glory). It's even possible to mine multiple gems from the same rock.

Wearing a charged amulet of glory and ring of wealth increases a player's chances of unearthing a gem while mining. However, one does not receive any additional Mining experience if one manages to mine a gem in such a fashion. As a free player without any amulet, you can obtain multiple gems of different kinds at one time from mining (at least two), but this is extremely rare. In such cases, members wearing a ring of wealth may potentially obtain four or more gems from mining one rock, though this is an even rarer occurrence. Furthermore, though uncommon, it is possible for a free player, whilst mining a rock and competing with another for its ore, to lose the ore to the other player, but manage to find a gem all the same.